Rotary positioning

ABSTRACT

An apparatus and associated method for rotary positioning is provided in an apparatus having an outer housing disposed around an inner housing, wherein at least one of the housings is rotatable with respect to the other housing. The rotary positioner also has a utility circuit having a first flexible circuit connected at one end to the outer housing and connected at an opposing end to the inner housing and forming a loop therebetween having a first u-shaped bend pointing in a first rotational direction in a space between the housings, and having a second flexible circuit connected at one end to the outer housing and connected at an opposing end to the inner housing and forming a loop therebetween having a second u-shaped bend pointing in a second rotational direction opposite to the first rotational direction in the space between the housings.

BACKGROUND

Rotary devices are widely used in the construction of machinery topermit the selective rotation of a workpiece, such as a component or atool and the like. In automated fabrication and assembly devices, forexample, some end effectors are constructed to have an extensiblegripping member supported by a rotary positioner so that a grippedworkpiece can be rotated in order to place it at different possiblerotational orientations.

Generally, such a rotary positioner typically has a fixed structure anda rotating structure. Often times it is necessary to traverse theinterface between the fixed and rotating structures with hardware thatsupplies a utility to the rotating structure, such as in communicatingelectrical energy or in supplying fluidic energy to the rotatingstructure.

As for electrical utilities, some previously attempted solutions employa slip ring to construct a rotating electrical connector. However, aslip ring requires a continuous contacting engagement between circuitterminals and a rotating part, which disadvantageously presents wear andtear issues and particulate contamination issues. Also, slip rings donot provide a hard-wired solution for applications where controllingelectrostatic discharge is a requirement.

As for fluidic utilities, some previously attempted solutions employ arotary union to construct a rotating fluidic connector. However, arotary union is inherently not well suited for miniaturization; even arotary union for a small workpiece application is disadvantageously big,bulky, and cumbersome to incorporate into an automated system.Furthermore, the stiction created by the moving seals in a rotary unioncreates problematic torque and position control issues.

These individual disadvantages associated with using a slip ring or arotary union are compounded in a system that requires both electricaland fluidic utilities be provided to the rotating structure, meaningthat both a slip ring and a rotary union are employed. Improvements areneeded in the manner of passing power utilities to the rotatingstructure of a rotary positioner to resolve these disadvantagesassociated with the previously attempted solutions. It is to thoseimprovements that the embodiments of the present invention are directed.

SUMMARY OF THE INVENTION

In some embodiments a rotary positioner is provided having an outerhousing disposed around an inner housing, wherein at least one of thehousings is rotatable with respect to the other housing. The rotarypositioner also has a utility circuit having a first flexible circuitconnected at one end to the outer housing and connected at an opposingend to the inner housing and forming a loop therebetween having a firstu-shaped bend pointing in a first rotational direction in a spacebetween the housings, and having a second flexible circuit connected atone end to the outer housing and connected at an opposing end to theinner housing and forming a loop therebetween having a second u-shapedbend pointing in a second rotational direction opposite to the firstrotational direction in the space between the housings.

In some embodiments a rotary positioner is provided that has an outerhousing disposed around an inner housing, wherein at least one of thehousings is rotatable with respect to the other housing. The rotarypositioner also has a utility circuit having first and second flexiblecircuits, each flexible circuit connected at a proximal end to the outerhousing and connected at a distal end to the inner housing and forming aslack loop therebetween in a space between the housings, the slack loopshaving respective bends pointing in opposite directions so that rotationof the rotatable housing in a first direction unwinds the first flexiblecircuit from the outer housing and winds the first flexible circuit tothe inner housing, and simultaneously unwinds the second flexiblecircuit from the inner housing and winds the second flexible circuit tothe outer housing.

In some embodiments a method is provided including the step of obtaininga rotary positioner having an outer housing disposed around an innerhousing, wherein one of the housings is rotatable with respect to theother housing, and having first and second flexible utility circuits,each flexible utility circuit connected at a proximal end to the outerhousing and connected at a distal end to the inner housing and forming aloop therebetween in a space between the housings, the loops havingrespective bends pointing in opposite directions. The method alsoincludes the step of rotating the rotatable housing in a firstrotational direction to unwind the first flexible circuit from the outerhousing and wind the first flexible circuit to the inner housing, and tosimultaneously unwind the second flexible circuit from the inner housingand wind the second flexible circuit to the outer housing.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an elevational depiction of an end effector that isconstructed in accordance with embodiments of the present invention.

FIG. 2 is a bottom-end view of the end effector of FIG. 1.

FIG. 3 is a cross-sectional depiction of one of the flexible circuits ofthe end effector of FIG. 1 used to communicate pressurized fluid.

FIG. 4 is a cross-sectional depiction of the rotatable inner housing andthe stationary outer housing in the end effector of FIG. 1.

FIG. 5 is a cross-sectional depiction of another one of the flexiblecircuits of the end effector in FIG. 1 used to communicate electricalenergy.

FIG. 6 diagrammatically depicts the rotary track portion of thebottom-end view of FIG. 2 at the extent of clockwise rotation of theinner housing.

FIG. 7 diagrammatically depicts the rotary track portion of thebottom-end view of FIG. 2 at the extent of counter-clockwise rotation ofthe inner housing.

FIG. 8 is a view similar to FIG. 6 but with the addition of a yoke inthe space between the inner and outer housings.

FIG. 9 is a view similar to FIG. 7 but with the addition of a yoke inthe space between the inner and outer housings.

DETAILED DESCRIPTION

The embodiments of the present invention contemplate an apparatus and anassociated method for rotationally positioning a workpiece. A rotarypositioner device is disclosed that includes a rotary track thatoperably communicates utilities across an interface between a rotatingportion and a stationary portion of the device. The utilities can becharacterized as electrical energy (power or signals) traversing theinterface via wiring, or can be characterized as fluid energy (power orsignals) traversing the interface via tubing, and the like.

Although the description that follows describes a rotary positionerutilized in an end effector of an automated production machine, thedescribed embodiments are merely illustrative and not limiting of thescope of the invention as claimed. The skilled artisan having read thisdisclosure readily recognizes equivalent alternative uses of the claimedinvention exist, such as but not limited to being employed as aconstituent component in a mechanical linkage or transmission and thelike.

Thus, FIG. 1 depicts an elevational view of an end effector 100 that isconstructed in accordance with illustrative embodiments of the presentinvention. The end effector 100 is mounted to a structural framework 102to position a gripper assembly 104 at a lower end thereof in anappropriate position or sequence of positions to manipulate a workpiece(not shown) as desired.

The gripper assembly 104 is selectively rotatable by a rotary positionerfeature. To that end, a motor 106 transfers rotational motion via belt112 to rotate an inner housing portion (shown below). FIG. 2 is abottom-end view of the gripper assembly 104 depicting the stationaryouter housing 114 disposed around the rotatable inner housing 116,although the scope of the claimed invention is not limited to thesedisclosed embodiments. That is, in alternative equivalent embodimentsonly the outer housing 114 is selectively rotatable and in otheralternative embodiments both the outer housing 114 and the inner housing116 are selectively rotatable. The skilled artisan can readily adapt thedisclosed embodiments to those alternative embodiments such that a fullenumeration of all possible variations is not necessary for anunderstanding of the scope of the claimed subject matter.

A utility circuit traverses the interface between the outer housing 114and the inner housing 116 to provide utilities to the inner housing 116.The utility circuit has a first flexible circuit 118 connected at oneend 120 to the outer housing 114 and connected at an opposing end 122 tothe inner housing 116, forming a slack loop therebetween having au-shaped bend 124 pointing in a counter-clockwise rotational directionwithin a space between the housings 114, 116. The utility circuitfurther has a second flexible circuit 126 connected at one end 128 tothe outer housing 114 and connected at an opposing end 130 to the innerhousing 116, forming a slack loop therebetween having a u-shaped bend132 pointing in a clockwise rotational direction within the spacebetween the housings 114, 116.

FIG. 3 is a cross sectional depiction of the first and second flexiblecircuits 118, 126 showing they are constructed of flexible tubingdefining a cavity 133 to communicate fluidic energy, such as pressurizedfluid or vacuum, to a gripper cylinder 134 (FIG. 2). The flexiblecircuits 118, 126 can be isolated with respect to each other tocommunicate characteristically different utilities. That is, withoutlimitation, pressurizing the flexible circuit 118 while venting theflexible circuit 126 can be designed to extend the gripper cylinder 134in order to actuate a clamp 136 to a clamped mode. Subsequently ventingthe flexible circuit 118 and pressurizing the flexible circuit 126retracts the gripper cylinder 134 to switch the clamp 136 from theclamped mode to an unclamped mode. The clamp 136 is sized with respectto workpieces (not shown) so that the clamp 136 grippingly engages theworkpiece in the clamped mode but clearingly disengages the workpiece inthe unclamped mode.

FIG. 4 is a diagrammatic cross sectional view depicting how the innerhousing 116 and outer housing 114 have close mating surfaces at theinterface 137 therebetween. Both of the housings 114, 116 definecavities that are sized to receivingly engage and support the flexiblecircuits (such as 126, 156 depicted) while the inner housing 116rotates. The upper continuous surface and opposing cavities function asa rotary track that guides and supports the slack loops during rotationof the inner housing 116.

The illustrative embodiments depicted by FIG. 2 have three such pairedslack loops pointing in opposite directions, although the claimedembodiments are not so limited. In alternative equivalent embodimentsthere can be one or more such paired slack loops. The lengths of theoppositely paired slack loops cooperatively permit the desired amount ofrotation. That is as is better depicted by comparing FIGS. 6 and 7 asdiscussed below, during rotation one of the slack loops winds off theinner housing 116 to provide clearance for the other slack loop to windonto the inner housing 116, depending on the direction of rotation. Thesame is true for the outer housing 114. Thus, the slack loops inembodiments having only one pair can be relatively longer thanembodiments with multiple pairs. Testing during reduction to practice ofthe embodiments of FIG. 2 indicated that more than ninety degrees ofrotation is achievable with the three pairs of slack loops.

The embodiments of FIG. 2 discussed below also contemplate two pairs ofslack loops being used to communicate fluidic energy and the other pairbeing used to communicate electrical energy, although the presentembodiments are not so limited. For example, in equivalent alternativeembodiments all the pairs could be used to communicate the same utility,or one or more pairs could be used to communicate control signals, andthe like.

Staying with FIG. 2, similar to the first and second flexible circuits118, 126, the utility circuit further has a third flexible circuit 138connected at one end 140 to the outer housing 114 and connected at anopposing end 142 to the inner housing 116, forming a slack looptherebetween having a u-shaped bend 144 pointing in the clockwiserotational direction in the space between the housings 114, 116. Afourth flexible circuit 146 is connected at one end 148 to the outerhousing 114 and connected at an opposing end 150 to the inner housing116, forming a slack loop therebetween having a fourth u-shaped bend 152pointing in the counter-clockwise rotational direction in the spacebetween the housings 114, 116.

Like the first and second flexible circuits 118, 126, the third andfourth flexible circuits 138, 146 are constructed of flexible tubing tocommunicate fluidic energy to selectively extend and retract a grippercylinder 154, respectively, in order to actuate the clamp 136 betweenthe clamped and unclamped modes.

The utility circuit further has a fifth flexible circuit 156 connectedat one end 158 to the outer housing 114 and connected at an opposing end160 to the inner housing 116, forming a slack loop therebetween having au-shaped bend 162 pointing in the counter clockwise direction in thespace between the housings 114, 116. Finally, the utility circuit has asixth flexible circuit 164 connected at one end 166 to the outer housing114 and connected at an opposing end 168 to the inner housing 116,forming a slack loop therebetween having a u-shaped bend 170 pointing inthe clockwise rotational direction in the space between the housings114, 116.

FIG. 5 is a cross sectional depiction of the fifth and sixth flexiblecircuits 156, 164 showing they are constructed of electrical wiring forcommunicating electrical energy, which for purposes of this descriptionand meaning of the claims means either electrical power or electricalsignals and the like. The depicted flexible circuits 156, 164 consist ofan outer protective sheath 172 that encases electrical conductors 174.The conductors 174 can be individually insulated to transmit differentthings, such as different legs of power or different signals. Traversingthe interface between the housings 114, 116 with such an electricalcommunication permits providing power or control signals to theworkpiece being handled by the gripper assembly 104.

FIGS. 6 and 7 are diagrammatic functional depictions of the rotary trackdepicted in the bottom-end view of the gripper assembly 104 in FIG. 2.The slack loops are all diagrammatically depicted by a single centerlinefor clarity sake. FIG. 6 depicts the inner housing 116 having beenrotated to the extent of rotational movement in the clockwise direction,and FIG. 7 conversely depicts the inner housing 116 having been rotatedto the extent of rotational movement in the counter-clockwise direction.

The three paired slack loops are individually long enough to permit theinner housing 116 to rotate up to about 95 degrees between the opposingextents of rotation. That amount of rotational movement is made possibleby the pairing up of oppositely pointing slack loops. That is, at theclockwise extent of rotational movement depicted in FIG. 6 both ends122, 130 of the first and second flexible circuits 118, 126 connected tothe inner housing 116 are angularly disposed on one side of the otherends 120, 128 of the first and second flexible circuits 118, 126connected to the outer housing 114. However, FIG. 7 shows that when theinner housing 116 is rotated to the counter-clockwise extent ofrotational movement, the ends 122, 130 of the first and second flexiblecircuits 118, 126 connected to the inner housing 116 are angularlydisposed on the other side of the opposing ends 120, 128 of the firstand second flexible circuits 118, 126 connected to the outer housing114.

As described, the paired up slack loops form oppositely pointing bends(such as 124, 132). Thus, the result of rotation of the housing 116 inthe clockwise direction is that the first flexible circuit 118 unwindsfrom the inner housing 116 and winds to the outer housing 114.Simultaneously, the second flexible circuit 126 unwinds from the outerhousing 114 and winds to inner housing 116.

FIGS. 8 and 9 are the similar to FIGS. 6 and 7 but with the addition ofa yoke 180 that is pinned at a proximal end at the axis of rotation ofthe inner housing 116, although the claimed embodiments are not solimited. That is, it will be understood that the purpose for pinning theyoke 180 is generally to guide it within the space between the housings114, 116 during rotation. In equivalent alternative embodiments the yoke180 can be guided without pinning it, such as but not limited toproviding it with a bearing surface that contactingly engages one orboth of the housings 114, 116 or the slack loops or both duringrotation.

The illustrative yoke 180 generally includes a framework for supportinga plurality of rollers 182 in the space between the housings 114, 116,although the present embodiments are not so limited. That is, inequivalent alternative embodiments other engagement members such as butnot limited to slider surfaces can be used. The span between theoutermost rollers 182 defines the arc length of the slack loop, in thatthey define arcuate surfaces around which the flexible circuits aretrained while winding from or winding to the housings 114, 116 duringrotation of the inner housing 116. The outermost rollers 182 therebysupportingly engage the u-shaped bends to prevent kinking.

The present embodiments further contemplate a method including the stepof obtaining the rotary positioner described above having the outerhousing 114 disposed around the inner housing 116, wherein one of thehousings is rotatable with respect to the other housing, and having thefirst and second flexible utility circuits, each flexible utilitycircuit connected at a proximal end to the outer housing 114 andconnected at a distal end to the inner housing 116 and forming a slackloop with oppositely pointing bends in the space between the housings114, 116. The method further includes the step of rotating the rotatablehousing to unwind the first flexible circuit from the outer housing tothe inner housing, and to simultaneously unwind the second flexiblecircuit from the inner housing to the outer housing.

The foregoing discussion has been presented for purposes of illustrationand description. The foregoing is not intended to limit the embodimentsto the form or forms disclosed herein. In the foregoing for example,various features of the claimed invention are grouped together in one ormore embodiments for the purpose of streamlining the disclosure. Thismethod of disclosure is not to be interpreted as reflecting an intentionthat the claimed invention requires more features than are expresslyrecited in each claim. Rather, as the following claims reflect,inventive aspects lie in less than all features of any of the disclosedembodiments. Thus, the following claims are hereby incorporated intothis description, with each claim standing on its own as separateembodiments of the invention.

Moreover, though the description of the claimed invention has includeddescription of one or more embodiments and certain variations andmodifications, other variations and modifications are within the scopeof the claimed invention, e.g. as may be within the skill and knowledgeof those in the art, after understanding the present disclosure. It isintended to obtain rights which include alternative embodiments to theextent permitted, including alternate, interchangeable and/or equivalentstructures, functions, ranges or steps to those claimed, whether or notsuch alternate, interchangeable and/or equivalent structures, functions,ranges or steps are disclosed herein, and without intending to publiclydedicate any patentable subject matter.

1. A rotary positioner comprising: an outer housing disposed around aninner housing, wherein at least one of the housings is rotatable withrespect to the other housing; and a utility circuit having a firstflexible circuit connected at one end to the outer housing and connectedat an opposing end to the inner housing and forming a loop therebetweenhaving a first u-shaped bend pointing in a first rotational direction ina space between the housings, and having a second flexible circuitconnected at one end to the outer housing and connected at an opposingend to the inner housing and forming a loop therebetween having a secondu-shaped bend pointing in a second rotational direction opposite to thefirst rotational direction in the space between the housings.
 2. Therotary positioner of claim 1 wherein the utility circuit furthercomprises a third flexible circuit connected at one end to the outerhousing and connected at an opposing end to the inner housing andforming a loop therebetween having a third u-shaped bend pointing in thefirst rotational direction in the space between the housings.
 3. Therotary positioner of claim 2 wherein the utility circuit furthercomprises a fourth flexible circuit connected at one end to the outerhousing and connected at an opposing end to the inner housing andforming a loop therebetween having a fourth u-shaped bend pointing inthe second rotational direction in the space between the housings. 4.The rotary positioner of claim 3 wherein the utility circuit furthercomprises a fifth flexible circuit connected at one end to the outerhousing and connected at an opposing end to the inner housing andforming a loop therebetween having a fifth u-shaped bend pointing in thefirst rotational direction in the space between the housings.
 5. Therotary positioner of claim 4 wherein the utility circuit furthercomprises a sixth flexible circuit connected at one end to the outerhousing and connected at an opposing end to the inner housing andforming a loop therebetween having a sixth u-shaped bend pointing in thesecond rotational direction in the space between the housings.
 6. Therotary positioner of claim 1 wherein the first flexible circuit andsecond flexible circuit are isolated with respect to each other andcommunicate different utilities between the outer and inner housings. 7.The rotary positioner of claim 6 wherein at least one of the first andsecond flexible circuits comprises an annular tube configured forcommunicating fluidic energy between the outer and inner housings. 8.The rotary positioner of claim 6 wherein at least one of the first andsecond flexible circuits comprises a conductor configured forcommunicating electrical energy between the outer and inner housings. 9.The rotary positioner of claim 1 further comprising a yoke rotated bythe rotatable housing and defining an arcuate surface in the spacebetween the housings that is sized to supportingly engage one of theu-shaped bends.
 10. The rotary positioner of claim 9 wherein the yokedefines two arcuate surfaces in the space between the housings that aresized to simultaneously supportingly engage two different u-shapedbends.
 11. The rotary positioner of claim 1 wherein both ends of thefirst and second flexible circuits connected to the inner housing areangularly disposed on one side of the opposing ends of the first andsecond flexible circuits connected to the outer housing at an extent ofrotational movement in the first rotational direction, and wherein bothends of the first and second flexible circuits connected to the innerhousing are angularly disposed on the other side of the opposing ends ofthe first and second flexible circuits connected to the outer housing atan extent of rotational movement in the second rotational direction. 12.The rotary positioner of claim 1 wherein the first and second flexiblecircuits are long enough to operably permit at least ninety degrees ofrotation between the housings.
 13. A rotary positioner comprising: anouter housing disposed around an inner housing, wherein at least one ofthe housings is rotatable with respect to the other housing; and autility circuit having first and second flexible circuits, each flexiblecircuit connected at a proximal end to the outer housing and connectedat a distal end to the inner housing and forming a slack looptherebetween in a space between the housings, the slack loops havingrespective bends pointing in opposite directions so that rotation of therotatable housing in a first direction unwinds the first flexiblecircuit from the outer housing and winds the first flexible circuit tothe inner housing, and simultaneously unwinds the second flexiblecircuit from the inner housing and winds the second flexible circuit tothe outer housing.
 14. The rotary positioner of claim 13 wherein thefirst flexible circuit and second flexible circuit are isolated withrespect to each other and operably communicate different utilitiesbetween the outer and inner housings.
 15. The rotary positioner of claim14 wherein at least one of the first and second flexible circuitscomprises an annular tube configured for operably communicating fluidicenergy.
 16. The rotary positioner of claim 14 wherein at least one ofthe first and second flexible circuits comprises a conductor configuredfor operably communicating electrical energy.
 17. The rotary positionerof claim 13 further comprising a yoke rotated by the rotatable housingand defining arcuate surfaces in the space between the housings that aresized to operably supportingly engage the flexible circuit at therespective bends.
 18. The rotary positioner of claim 13 wherein bothends of the first and second flexible circuits connected to the innerhousing are angularly disposed on one side of both ends of the first andsecond flexible circuits connected to the outer housing at an extent ofrotational movement in the first rotational direction, and wherein bothends of the first and second flexible circuits connected to the innerhousing are angularly disposed on the other side of both ends of thefirst and second flexible circuits connected to the outer housing at anextent of rotational movement in the second rotational direction. 19.The rotary positioner of claim 13 wherein the first and second flexiblecircuits are long enough to operably permit at least ninety degrees ofrotation between the housings from the extent of rotation in the firstrotational direction to the extent of rotation in the second rotationaldirection.
 20. A method comprising: obtaining a rotary positioner havingan outer housing disposed around an inner housing, wherein one of thehousings is rotatable with respect to the other housing, and havingfirst and second flexible utility circuits, each flexible utilitycircuit connected at a proximal end to the outer housing and connectedat a distal end to the inner housing and forming a loop therebetween ina space between the housings, the loops having respective bends pointingin opposite directions; and rotating the rotatable housing in a firstrotational direction to unwind the first flexible circuit from the outerhousing and wind the first flexible circuit to the inner housing, and tosimultaneously unwind the second flexible circuit from the inner housingand wind the second flexible circuit to the outer housing.